The present invention relates to firefighting systems in general and particularly to a means by which chemical agent additives can be successfully applied to a fire by remotely controlled equipments.
There are a number of situations in which firefighting is extremely difficult, if not impossible, with conventional fire-fighting equipments such as moving a fire truck overland to the point of need, or in cases where no water supply mains exist. Examples are forest fires in rugged impassable terrain and forward area military air strips or pads under combat situations. Recent developments in the use of short takeoff and landing and helicopter craft have created requirements for remotely located refueling and resupply dumps. Fire fighting efforts in such situations can be enhanced by providing air transportable ground support equipments which can be quickly moved into a site or prepositioned. Such equipments should be designed to be transported swiftly from site to site. Loss of fuel and supplies due to fire in military situations can easily neutralize the combat readiness of a dependent force. In many situations, such as fuel dump, ammo dump, forest conflagration and toxic gas or chemical fires, extreme hazards are faced by fire fighting personnel. Within the civilian sector, extremely wide dispersal of luxurious housing and light industry into rural and "rustic" areas has occured. Therefore, a need exists for a remotely controlled fire fighting capability. This presents special problems when chemical agent additives are utilized in the fire suppressant (e.g., water).
Suppressants including chemical additives mixed in very small quantities with water greatly enhance the fire fighting capabilities of the water. There have been three ways in which these chemicals have been injected and mixed with the water: premixing in water storage containers; use of around-the-pump proportioners; and use of eductors. Each of these means has certain limitations which are not compatible with the highly mobile fire fighting system developed and discussed herein.
Premixing the chemicals with stored water is applicable particularly for wetting agents. However, some of the additives are corrosive and must be stored in special containers until required for use. Mixing by means of around-the-pump proportioners is suited to systems and situations with "unlimited" water sources and close supervision by experienced fire fighting personnel. Application by means of eductors which function on the venturi principle requires careful selection and matching of eductor size to the water stream flow rate and pressure. Eductors are also sensitive to pressure drop across the eductor and therefore placement is most effective at the nozzle end of the water stream.
Based upon the needs for fire protection in forward area combat situations a highly mobile fire fighting system featuring remote control of the placement of fire suppressants onto the fire has been developed.
The highly mobile fire fighting system incorporates two basic types of modules; water storage and mechanical equipment (pump and engine). The intended use for the system envisions long term storage of water supplies when prepositioned or for movement from site to site, and therefore, limits means for introduction of the corrosive chemical additives. Because of anticipated long-term water storage, permixing of chemical additives is not a practicable solution. The mechanical system includes a continuous recirculation bypass for fire pump cooling when valving downstream is closed intermittently. This would upset a chemical additive mixture proportioned by an around-the-pump system. The highly mobile fire fighting system incorporates a standoff fire fighting capability wherein the operator controls a fire nozzle transporter vehicle remotely, from distances up to 1,500 feet. This standoff distance is intentionally variable, and is determined by the number of 50 foot lengths of fire hose required to reach the fire objective. Consequently, utilization of eductors as the additive injection method also is not practicable. Because of the corrosive nature of the chemical additives, materials compatibility becomes a problem and cleaning up after use is essential.